Lanthanide-regulating Ru-O covalency optimizes acidic oxygen evolution electrocatalysis
Lu Li, Gengwei Zhang, Chenhui Zhou, Fan Lv, Yingjun Tan, Ying Han, Heng Luo, Dawei Wang, Youxing Liu, Changshuai Shang, Lingyou Zeng, Qizheng Huang, Ruijin Zeng, Na Ye, Mingchuan Luo, Shaojun Guo
Abstract
Abstract Precisely modulating the Ru-O covalency in RuO x for enhanced stability in proton exchange membrane water electrolysis is highly desired. However, transition metals with d -valence electrons, which were doped into or alloyed with RuO x , are inherently susceptible to the influence of coordination environment, making it challenging to modulate the Ru-O covalency in a precise and continuous manner. Here, we first deduce that the introduction of lanthanide with gradually changing electronic configurations can continuously modulate the Ru-O covalency owing to the shielding effect of 5 s /5 p orbitals. Theoretical calculations confirm that the durability of Ln-RuO x following a volcanic trend as a function of Ru-O covalency. Among various Ln-RuO x , Er-RuO x is identified as the optimal catalyst and possesses a stability 35.5 times higher than that of RuO 2 . Particularly, the Er-RuO x -based device requires only 1.837 V to reach 3 A cm −2 and shows a long-term stability at 500 mA cm −2 for 100 h with a degradation rate of mere 37 μV h −1 .